One preferred embodiment of the present invention provides a housing or ejection mechanism comprising sliding contacts for contacting side contacts of a plate-like memory or I/O card, which are two examples of a PC card. Such an embodiment is disclosed herein. However, it should be noted that, except as they may be expressly so limited, the claims at the end of this specification are not limited to such ejection mechanisms.
Plate-like integrated circuit cards, or PC cards, have become increasingly popular for use in notebook, laptop, and desktop computers, as well as other consumer products. Standard specifications from the Personal Computer Memory Card International Association (PCMCIA) and the Japan Electronic Industry Development Association (JEIDA) have helped to expand this relatively new industry. Other standard specifications have been developed by the Joint Electron Device Engineering Council (JEDEC). Although commonly referred to as "memory cards," these cards are by no means limited to data storage applications. For example, some cards perform various I/O functions for modem and local area network applications.
Currently, the PCMCIA/JEIDA standard cards incorporate a sixty-eight pin female connector at one end, and are available in three formats. Type I houses SRAM, PSRAM, MROM, OPTROM, and flash memory chips and only performs memory functions. Type I cards have a thickness of 3.3 mm. Type II cards perform I/O functions for modem and local area network (LAN) applications. The side edges of Type II cards are 3.3 mm thick; however, the main body of the cards is 5.0 mm thick. Type III cards are really not "cards" but rather are 1.8 inch hard disk drives having a 10.5 mm thick housing. However, these cards too are equipped with outside edges of 3.3 mm.
Given the increasing popularity of these PC cards, a need has arisen for suitable connector devices for connecting these cards to printed circuit boards in host devices, such as notebook, laptop and desktop computers. A number of connector devices have appeared in the prior art. Prior art connector devices typically comprise some sort of frame or housing into which a memory card may be inserted. A contact header with an array of pin contacts is provided at the far end of the housing to connect with a corresponding contact array disposed in the front end of the memory card. Connector devices typically employ an ejection mechanism having an ejector plate that engages with the PC card, a lever mounted on the housing and coupled at one end to the ejector plate, and a push rod coupled to the other end of the lever. To eject a card, the push rod is driven toward the contact header. Movement of the push rod toward the contact header is translated through the lever into movement of the ejector plate away from the contact header. As the ejector plate moves away from the contact header, it engages with the memory card thereby disconnecting the memory card from the array of contacts on the header and urging the memory card backward out of the connector device. Further information on the design of a housing with an ejection mechanism is disclosed in copending application Serial No. 08/131,212 filed Oct. 1, 1993, and titled "A Connector Apparatus for Memory Cards Having a One-Piece Integrated Frame," which is hereby incorporated by reference.
Another area of development involves the addition of so called side-swipe contact areas along the lateral sides of a PCMCIA-compatible PC card. The current PCMCIA standard defines a sixty-eight pin connector for use by a host system for control and data transfer to the PC card. Only one of the sixty-eight pins (pin 57) is available for signal propagation specific to the function of the card. For example, pin 57 is available to carry tip and ring signals on a modem card. Alternatively, the I/O connector may be allowed (by the PCMCIA committee) to provide a mechanism for signal propagation. However, this would require an external connection on the end of the PC card.
With the newly developed side contact on the PC card, signals may be propagated through the side of the card and routed internally to the appropriate connector on the host platform. In this manner, users of PC cards are only required to carry the PC card while still maintaining system functionality. However, such a system requires a host system header or ejection mechanism that provides side-swipe contacts. Moreover, it is required that the side-swipe contacts provide both a good electrical contact when a PC card is fully inserted in the host system header or ejection mechanism and an easy sliding fit allowing the card to be easily slid in and out of the ejection mechanism.
Prior art patents have disclosed side contact arrangements for printed circuit boards (PCBs). For example, U.S. Pat. No. 3,576,515, Apr. 27, 1971, "Printed Circuit Edge Connector," discloses a PCB edge connector for connecting a plurality of stacked PCBs having connector elements extending outwardly from the edges of the respective PCBs. As depicted in FIGS. 1 and 2 of the patent, when inserting a PCB into the connector housing, two pins are passed through apertures extending the entire length of the housing. The pins, during movement through the aperture, abut the connectors and force the connectors away from the slot through which the PCB slides. In this way, the PCB can be slid along the grooves of the connector housing for the full length thereof while the pin is inserted and is biasing the connectors in the connector housing out of the path of travel. Upon removal of the pins, the connectors in the connector housing assume their original position due to their resiliency or spring action and abut the terminals of the printed circuit to complete the electrical connection.
This arrangement is undesirable because, among other things, the requirement that pins be employed in order to insert the PCB into the respective slots of the housing makes this arrangement unacceptably difficult to use and expensive. Moreover, it is unsuitable for use in connection with an ejection mechanism for PC cards, the preferred application of the present invention.
U.S. Pat. No. 4,017,770, Apr. 12, 1977, "Connecting Device for Telecommunication Circuits," discloses a connecting device comprising a rectangular frame of insulating material having guide grooves that engage the edges of a PCB. Connectors on the frame consist of areas of conductive material disposed on the inner face of each of the two opposite sides of the frame. In the embodiment depicted in FIG. 3 of the patent, the movable PCB is provided, on the edges engaging the grooves, with contact springs which provide for the desired connection between the circuit on the PCB and the connectors on the frame when the board is inserted in the frame.
This approach is unacceptable for applications involving PC cards because it requires the cards to be modified by adding contact springs along their sides. Moreover, the use of contact springs as disclosed in the patent would not provide both a good electrical contact when a card is fully inserted in the grooves of the side rails and an easy sliding fit allowing the card to be easily slid in and out of the side rails. This is because the force of the spring varies as the spring is compressed and expanded. Therefore, a spring that, when extended, provides a suitable force to provide a good electrical connection also necessarily provides, when compressed, too much force during sliding of the PCB in the grooves of the housing.
Accordingly, a primary goal of the present invention is to provide a sliding contact arrangement, suitable for use with PC cards and the like, which allows the card to be easily slid in and out of an ejection mechanism and, furthermore, provides a good electrical connection with the side contacts of the PC card.